单项选择题

A.戊巴比妥,pKa8.0(未解离率80%)
B.苯巴比妥,pKa7.4(未解离率50%)
C.异戊巴比妥,pKa7.9(未解离率75%)
D.苯巴比妥酸,pKa3.75(未解离率0.022%)
E.海索比妥,pKa8.4(未解离率90%)